R devel - Jan 2003 - Warning appears after update.packages() (PR#2459)

Full_Name: Joaquin Diaz-Saiz
Version: 1.6.2
OS: Windows 98
Submission from: (NULL) (129.7.121.92)

> update.packages()
trying URL `http://cran.r-project.org/bin/windows/contrib/PACKAGES'
Content type `text/plain; charset=iso-8859-1' length 8721 bytes
opened URL
downloaded 8721 bytes

Warning message: 
DLL attempted to change FPU control word from 8001f to 9001f 


NOTE: IS THIS OF ANY IMPORTANCE? IT DID NOT APPEAR IN VERSION 1.6.1.

On Wed, 15 Jan 2003 22:41:49 +0100 (MET), you wrote:
>Full_Name: Joaquin Diaz-Saiz
>Version: 1.6.2
>OS: Windows 98
>Submission from: (NULL) (129.7.121.92)
>
>
>> update.packages()
>trying URL `http://cran.r-project.org/bin/windows/contrib/PACKAGES'
>Content type `text/plain; charset=iso-8859-1' length 8721 bytes
>opened URL
>downloaded 8721 bytes
>
>Warning message: 
>DLL attempted to change FPU control word from 8001f to 9001f 
>
>
>NOTE: IS THIS OF ANY IMPORTANCE? IT DID NOT APPEAR IN VERSION 1.6.1.
Thanks for posting that. It tells you that an external dll has caused
the floating point precision to change, but R has changed it back.
It's a sign of a bug that needs fixing.  I'll look into it.

This change in mentioned in the CHANGES file.  You can read more about
it in the dyn.load help page.

Duncan Murdoch

On Thu, 16 Jan 2003 11:37:26 -0600, you wrote in message
<20030116113726.3e562214.JDiaz-Saiz@UH.EDU>:
>I just did what you suggested. I even turned the computer off and started
from scratch. The first time that I call update.packages() I get the warning. It
does not appear when calling the function again.
>
>My OS is Windows 98SE.
I've got some more information now.  The first time you do any
internet operation, R loads "internet2.dll" or
"internet.dll", which
are part of Internet Explorer.  Whichever one of those that you're
using has a bug in it:  it is changing the floating point precision
from 64 bit to 53 bit precision.  (This is a common bug in Microsoft C
and other DLLs.)

Versions of R previous to 1.6.2 would not correct this bug, and would
proceed to give you erroneous results.  You probably wouldn't notice
in most calculations, since 53 bits is still enough precision for most
purposes.  Version 1.6.2 corrects it by changing the precision back to
64 bits and giving you the warning, so R should be safe.

If something in the DLL relies on 53 bit precision, you might find
that it doesn't work any more.  This seems pretty unlikely:  after
all, 64 bit precision is better than 53 bit precision, and an Internet
browser doesn't do much with floating point in any case.  It'll likely
just run a tiny bit slower.

So my advice would be to ignore the error.  If you don't like that,
you could try upgrading to a newer version of Internet Explorer, and
the error might go away.  I'm using IE 5.50 in Win98 and I don't see
the message.

Duncan Murdoch